Scientists are working to develop a test that will allow doctors to screen for multiple cancer types from a single blood sample.

All cancers produce compounds that end up in the bloodstream, so it is feasible that such blood markers could form the basis of a general screening test for many different forms of cancer.

Cancer cells often start shedding blood markers long before many of the signs and symptoms of tumors begin to emerge, so earlier diagnosis can generally mean treatment is more effective, which, in turn, improves survival.